Lemonldap::NG::Handler versions from 2.0.0 before 2.16.10, from 2.17.0 before 2.21.6, from 2.22.0 before 2.23.4 for Perl allow an equivalent spelling of a path to bypass the locationRules that restrict it.
The handler matches each vhost's locationRules regular expressions against REQUEST_URI, the raw request line, while the web server routes on the path it has already percent-decoded and normalized. A request that percent-encodes a character of the path, inserts dot segments, or doubles a slash therefore reaches the protected resource under a URI that no rule regexp matches, and the vhost's default rule decides access. Deny rules, identity and group conditions, and unprotect and skip rules are bypassed alike.
Only a vhost whose default rule is more permissive than its other rules is affected. An authenticated user then reaches any URL a locationRules regexp was meant to restrict, but gains no more than that default rule already grants.
Upgrade to Lemonldap-NG-Handler 2.16.10, 2.21.6 or 2.23.4 or later. Only 2.23.4 is on CPAN; the 2.16.10 and 2.21.6 LTS releases are available from https://lemonldap-ng.org/download.html.